1. Field of the Invention
The present invention relates generally to computer security, and more particularly but not exclusively to methods and apparatus for web filtering.
2. Description of the Background Art
Some private computer networks have security policies that prohibit end users from accessing particular remote resources, such as certain websites and servers. For example, a corporation may prohibit employees from accessing some remote servers from within the corporate network. As another example, parents may choose to block particular websites from being accessed by their children. Access to remote resources may be controlled using commercially available policy enforcement products. These products may evaluate acceptability of a remote resource by domain name. For example, a policy enforcement product may receive a domain name of a resource being accessed by a user and block access to the resource based on the rating or category of the domain name. Some users circumvent policy enforcement by accessing a resource without using the resource's domain name. For example, a user may access a server by replacing domain names in uniform resource locators with an equivalent numeric IP (Internet protocol) address.